What is grape?
There are two main types of grapes: European grapes (Vitis vinifera) and North American grapes (Vitis labrusca andVitis rotundifolia). The European grapes (Vitis vinifera) represent 95 percent of grapes produced. The European grapes have a thick skin and sweet flesh which adheres firmly to the skin. The most important North American grape is the Concorde grape. The grape vine is a woody climber with more or less twisted stems and large lobbed leaves. The grape vine attaches to other plants with its coiled climbing tendrils. The grape flowers are small and are formed on a light green panicle. In autumn, the grape vine forms blue, red or green colored grape berries (or simple called grapes) that contains between 5 and 10 seeds.
Parts used
The grape fruits are eaten or used to make juice and wine. The grape seeds are an industrial raw material to produce grape seed extract, rich in antioxidant phytochemicals. Grape skins are also industrially processed into grape skin extract, which is used for its health benefits or used as natural color. Sometimes the grape leaves are used.
Phytochemicals
These are typical phytochemicals found in grape:
phenolic acids, flavonols, flavon-3-ols, myricetin, peonidin,
flavonoids,
resveratrol,
quercetin, tannins,
anthocyanins,
kaempferol,
cyanidin,
ellagic acid,
proanthocyanidins.
Benefits of grape
Red grapes and red wine contain levels of flavonoids which have antioxidant properties and help to reduce the risk for cancer and heart disease. These flavonoids also have an anti-inflammatory and anti-allergic effect. Red grape leaves have been traditionally used to treat diarrhea, heavy menstrual bleeding and uterine hemorrhage.
Heart disease
Several epidemiological studies have shown that moderate consumption of red wine has cardioprotective properties and can decrease coronary heart disease mortality. Studies have shown that quercetin and other polyphenols in wine prevent oxidation. Frankel et al showed in the study entitled "Inhibition in vitro of oxidation of human low density lipoproteins by phenolic compounds in wine" published in Lancet (1993, 39:1743-1748) that red wine protects low density lipoproteins from oxidation. The flavonoids ellagic acid and resveratrol have been shown to reduce the risk of coronary heart disease. Grape seed proanthocyanidins may have therapeutic potential in the prevention and treatment of vascular complications in diabetic patients.
Anti-cancer
Grape contains phenolic compounds, including resveratrol, flavon-3-ols, caffeic acid, ellagic acid and quercetin. Phenolic compounds have anticancer properties and have been correlated with the inhibition of various cancers, including colon, esophagus, lung, liver, mammary and skin cancers. Resveratrol can inhibit cancer formation in different ways: resveratrol stops DNA damage, improves DNA repair, slows down tumor growth and slows cell transformation from normal to cancerous. Jang et al demonstrated in his study "Cancer chemopreventive activity of resveratrol, a natural product derived from grapes" published in Science (1997, 275:218-220) that resveratrol has cancer chemopreventive activity in different stages of carcinogenesis. Resveratrol was found to act as an antioxidant and antimutagen and to induce phase II drug-metabolizing enzymes; it mediated anti-inflammatory effects and inhibited cyclooxygenase and hydroperoxidase functions. Not only red grape juice but grape seeds are rich in anticancer phytochemicals.
Antioxidant activity
Grape phenolics such as catechins, flavonols, anthocyanins and tannins have strong antioxidant activity and help to prevent oxidative damage. Grape antioxidants help to prevent the risk of several chronic and age related diseases including dementia, cancer, heart disease and cataracts.
Antibacterial and antiviral activity
A study by Pisha et al, entitled "Fruits and vegetables containing compounds that demonstrate pharmacological activity in humans" and published in Economic and Medicinal Plant Research (1994, 6:189-233), showed that grape phenolics possess antibacterial and antiviral activities. The following phytochemicals in grape have weak antibacterial activity: hydroxybenzoic acid, salicylic acid, gallic acid and protocatechuic acid. Chlorogenic acid and epicatechin have shown antiviral activity against some viruses.
Other facts
The grape originates from the Mediterranean regions from where it was introduced to all temperate regions. About 80 percent of grapes are used for the production of wine, mainly in France, Spain, California, South Africa, Chili and Argentina. Grapes are eaten as such or transformed into juice or wine. Grape pomace is the left-over product of wine production and contains considerable amounts of anthocyanins, which can be extracted.
Other names
Grape vine, vine
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